The invention is generally related to providing controllable translation of microcomponents and, more particularly, to providing independent translation of microcomponents in a plurality of directions.
There are many applications in which it may be desirable to provide controlled positioning of a microcomponent. For example, in optical technologies it may be desired to provide controlled movement of a lens with respect to a light source, such as a laser emitter, to produce desired light emission patterns. Similarly, it may be desired to provide controlled movement of an optical fiber end in order to properly interface with a light source.
Accordingly, various apparatuses, typically referred to as microelectromechanical systems (MEMS), have been developed to provide translation of a specimen in particular directions. For example, micro-translation systems have been developed in which a microcomponent stage, upon which a specimen may be placed or mounted, is operatively coupled to an actuator to provide controlled movement of the stage and, accordingly, translation of the specimen. Multiple actuators may be disposed in such a micro-translation system to provide a configuration in which motion in multiple directions may be provided, such as along both the X and Y axes.
One such micro-translation system utilizes a plurality of thermal actuators (also referred to as heatuators) for in-plane translation. Directing attention to FIG. 1, micro-translation system 100 is shown including thermal actuators 110 and 120 directly coupled to stage 130 by flexures. Thermal actuators 110 and 120 are oriented to provide translation of stage 130, and components placed thereon, along both the X and Y axes. Specifically, thermal actuator 110 is coupled to stage 130 by connecting member 131 and provides translation of stage 130 substantially along the X axis when hot-arm 111 is expanded by Joule heating and anchor 114, cold-arm 112, flexure 113, and anchor 115 cause transfer of torsional energy to connecting member (flexure) 131. Similarly, thermal actuator 120 is coupled to stage 130 by connecting member 132 and provides translation of stage 130 substantially along the Y axis when hot-arm 121 is expanded by Joule heating and anchor 124, cold-arm 122, flexure 123, and anchor 125 cause transfer of torsional energy to connecting member (flexure) 132.
It should be appreciated, however, that micro-translation systems of the prior art utilizing thermal actuators in such a configuration suffer from several disadvantages. One such disadvantage is that the motion actively imparted is unidirectional. Moreover, attempts to provide bi-directional motion using such micro-translation systems generally require substantial post-processing manufacturing steps, such as to electronically isolate the thermal actuators associated with different directions of motion, thereby making such systems impossible to fully implement with monolithic production processes. Additionally, the range of motion associated with the use of thermal actuators is limited to approximately 5% of the overall length of the actuator. A further disadvantage is that translation provided by the micro-translation system along either axis is not independent of translation along the other axis. For example, translation of stage 130 provided by thermal actuator 120 along the Y axis will result in some translation of stage 130 along the X axis due to the torsional distortion of thermal actuator 120. This movement along the unselected axis is further aggravated due to the connection of connecting member 131 and thermal actuator 110 thereto.
Other known micro-translation systems utilize indirect translation mechanisms. Directing attention to FIG. 2, unidirectional micro-translation system 200 is shown utilizing indirect drive means. In the system of FIG. 2, a translation mechanism is disposed on each side of, and in the same plane with, stage 230 to controllably engage stage 230 and provide translation in a predetermined direction. Specifically, translation mechanism 210 includes actuator banks 211 and 212 coupled to lateral translation gear 231 by connecting arms 214 and 215, respectively. Similarly, translation mechanism 220 includes actuator banks 221 and 222 coupled to lateral translation gear 232 by connecting arms 224 and 225, respectively. Actuator banks 211, 212, 221, and 222 may be comprised of an array of thermal actuators, such as are shown in detail above in FIG. 1, and are oriented to provide translation of stage 230, and components placed thereon, along the X axis by causing lateral translation gears 231 and 232 to engage corresponding racks 233 and 234 using Y axis movement associated with actuator banks 211 and 221. Thereafter, movement along the X axis is provided by lateral movement of engaged translation gears 231 and 232 causing corresponding movement in racks 233 and 234, and thus stage 230, using X axis movement associated with actuator banks 212 and 222. Lateral translation gears 231 and 232 may then be disengaged from corresponding racks 233 and 234, again using Y axis movement associated with actuators 211 and 221, and reengage with corresponding racks 233 and 234 at a different point, using X axis movement associated with actuators 212 and 222, for further movement of stage 230.
Micro-translation systems of the prior art utilizing the above described indirect thermal actuator drive mechanisms suffer from several disadvantages. For example, although the range of motion is appreciably improved over that of the direct thermal actuator drive mechanism of FIG. 1, the motion actively imparted remains unidirectional and, the only one direction of movement is provided. Moreover, attempts to provide bi-directional motion using such micro-translation systems generally require substantial post-processing manufacturing steps, such as to electronically isolate the actuator banks associated with different directions of motion, thereby making such systems impossible to fully implement with monolithic production processes. Additionally, prior art configurations of such micro-translation systems provide translation of a stage along a single axis and, therefore, no configuration has been proposed to provide movement along two axes which may be produced without substantial-post production manufacturing steps, i.e., no configuration is known in the prior art which may be produced using a monolithic manufacturing process.
Still other prior art micro-translation systems have implemented scratch drive actuators (SDAs) to provide translation of a stage. Directing attention to FIG. 3, one configuration of a SDA as is well known in the art is shown as SDA 310. Specifically, SDA 310 comprises plate 311, torsion mounts 312, and bushing 313. For operation, SDA 310 is disposed upon a substrate such that a conducting layer, such as conducting layer 322, is in juxtaposition with plate 311 and an insulating layer, such as insulating layer 321, is disposed therebetween.
Operation of SDA 310 is illustrated in FIGS. 4A-4C. Specifically, FIG. 4A shows voltage source 410 coupled to plate 311 and conducting layer 322 without any voltage applied thereto. However, as shown in FIG. 4B, a priming voltage may be provided by voltage source 410 and an electromagnetic field associated therewith causes deflection of plate 311 such that its distal end is drawn toward conducting layer 322. As shown in FIG. 4C, the voltage provided by voltage source 410 may be increased to that of a stepping voltage such that plate 311 is more fully drawn toward conducting layer 322 causing bushing 313 to be displaced such that a distal end thereof steps forward distance xe2x80x9cSxe2x80x9d. Reducing the voltage provided by voltage source 410 to the priming voltage or below causes plate 311 to move forward distance xe2x80x9cSxe2x80x9d as bushing 313 is again righted, i.e., SDA 310 returns to a orientation as shown in FIGS. 4A or 4B.
Although SDAs are generally useful in providing a relatively large range of linear motion, implementation of such actuators is still fraught with problems. For example, the use of such SDAs has generally required the use of a wire tether to provide activating potential to the SDA plate while accommodating the motion of the SDA. Moreover, although a bank of SDAs may be produced using a monolithic manufacturing process, all such SDAs have heretofore been electrically connected, causing each such SDA to be activated simultaneously. Accordingly, true bi-directional implementations of SDAs have not been provided using monolithic manufacturing processes as the SDAs of each such direction have been electrically connected and thus operable simultaneously. In order to provide SDAs which are independently operable in multiple directions, prior art implementations have required substantial post-processing manufacturing steps, such as to electronically isolate the SDAs associated with different directions of motion, thereby making such systems impossible to fully implement with monolithic production processes.
Accordingly, a need exists in the art for systems and methods to provide a relatively large range of motion in multiple directions with respect to a microcomponent. A need exists in the art for such multiple directions of motion to include bi-directional motion and/or motion along different axes.
Moreover, a need exists in the art for systems and methods to provide a relatively large range of motion which may be substantially produced using monolithic manufacturing processes.
The present invention is directed to systems and methods which provide controlled positioning of a microcomponent in a plurality of directions for which control is provided independently. Preferably, the present invention provides a relatively large range of motion for positioning a specimen or other component for subsequent use or manipulation, such as for performing a manufacturing step.
Preferred embodiments of the present invention provide a MEMS micro-translation system providing a relatively large range of motion, such as bi-directionally along an X axis, Which is adapted for production using monolithic manufacturing processes without requiring post-process manufacturing steps. Specifically, monolithic manufacturing of preferred embodiment micro-translation systems provide for operation of the micro-translation system throughout a relatively large range of motion without requiring post-processing manufacturing steps, i.e., without employing manufacturing steps with respect to a monolithically produced micro-translation system after its removal from the monolithic sustrate (after xe2x80x9cbreaking siliconxe2x80x9d).
For example, a plurality of actuator banks of a preferred embodiment monolithically produced micro-translation systems are provided with independent control, such as for providing independent motion in a plurality of different directions, without requiring a post-processing step, such as affixing actuator banks to a non-conductive stage or otherwise providing electrical isolation between actuators. Additionally or alternatively, preferred embodiments of the present invention are adapted to be controlled throughout such relatively large ranges of motion without the post-processing application of wire tethers thereto.
Preferred embodiments of the present invention provide independent microcomponent translation along multiple axes, e.g., provide translation along an X axis and a Y axis. Embodiments of the invention preferably utilize a configuration of actuators in which motion imparted by at least one actuator results in corresponding movement of an independently controllable actuator while the independently controllable actuator remains inactive. For example, a preferred embodiment implementation of the present invention provides a monolithically produced micro-translation system in which actuators are disposed in multiple device units, such that an actuator of a secondary device unit, for providing movement along a first axis, is moved along a second axis by operation of an actuator of a primary device unit.
Accordingly, a technical advantage of the present invention is that motion in multiple directions, e.g., bi-directionally and/or along different axes, is provided with independent control. Moreover, a further technical advantage of the present invention is that such motion may be provided throughout a relatively large range.
A still further technical advantage is that micro-translation systems of the present invention are preferably adapted for use of monolithic manufacturing processes in their production and, thus, eliminate or otherwise minimize the use of post-process manufacturing steps.
The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present invention.